Various application exist where it is desired to measure the torque applied by a user. In some applications the measured torque is used to produce a control signal which then performs another function.
The present invention is directed to a torque sensor for a device which includes a rotatable member. Such device can be, for example, an exercise machine, where the user grasps a handle, wheel, or bar and rotates it against a resistance to produce a torque force to achieve the effect of performing a desired type of exercise.
In a machine where a member is rotated against a resistance, the rotational torque, corresponding to the force that is being applied which is to be measured, the measurement of the torque can be made for evaluation purposes. Also, the torque measured can be used to produce a signal for controlling an arrangement for producing a resistance so that it can be maintained, or changed, to accommodate a particular applied force which is to work against the resistance.
The present invention is described with respect to an exercise mechanism although it can be used on any device in which torque is to be sensed. In a product line of exercise equipment, a wide range of torques may be applied by the user, since differing strengths of individuals and limbs are involved.
In addition, a speed control system must be considerably faster than the unit it is controlling. This means that a torque sensor and its associated components should respond quickly and preferably provide continuously available data to a high-speed microprocessor control system.
The flexibility to be able to sense torque applied to a continuously rotating shaft in either direction assists greatly in designing a variety of machines, including exercise apparatus that control cables or pulleys and makes human interaction to levers in differing positions and moving in differing directions for varying amounts of angular displacement much easier.